Methods of cutting or forming cavities in a substrate for use in making optical films, components or wave guides

ABSTRACT

A method of forming a varying pattern of optical elements on or in at least one side of an optical panel member involves cutting or forming a pattern or patterns of cavities in a cylindrical or curved substrate or in a sleeve or sleeve segment of the substrate that corresponds to a desired pattern and shape of optical elements to be formed on or in the optical member. The substrate or sleeve or sleeve segment containing the desired pattern or patterns of optical element shaped cavities or depositions or mirror copies or inverse copies thereof is used in production tooling or as a master for production tooling to form the corresponding pattern of optical elements on or in at least the one side of the optical panel member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/915,632, filed Aug. 10, 2004, now abandoned which is acontinuation-in-part of U.S. patent application Ser. No. 10/729,113,filed Dec. 5, 2003, now U.S. Pat. No. 7,090,389, dated Aug. 15, 2006,which is a division of U.S. patent application Ser. No. 09/909,318,filed Jul. 19, 2001, now U.S. Pat. No. 6,752,505, dated Jun. 22, 2004,which is a continuation-in-part of U.S. patent application Ser. No.09/256,275, filed Feb. 23, 1999, now U.S. Pat. No. 6,712,481, dated Mar.30, 2004, the entire disclosures of which are incorporated herein byreference.

FIELD OF THE INVENTION

This invention relates to methods of cutting or forming one or morepatterns of optical element shaped cavities in a substrate for use informing corresponding patterns of optical elements on or in opticalsubstrates including films, components or wave guides and the like.

BACKGROUND OF THE INVENTION

It is generally known to provide multiple optical elements on or in oneor more surfaces of optical substrates including films, components orwave guides for directing light passing through the optical substrates.At least some of the optical elements may have at least two surfacesthat come together to form a ridge and are quite small relative to thelength and width of the optical substrates.

It is generally known to cut or form a predetermined pattern of cavitiesof such optical element shapes in a flat sheet or plate using a millingor laser cutter and using the cut optical element shapes in the sheet orplate to form a corresponding pattern of optical elements on or inoptical substrates. A drawback to this method is the difficulty andexpense of cutting or forming cavities of certain types of opticalelement shapes including particularly those having at least two surfacesthat come together to form a ridge and are quite small relative to thelength and width of the optical substrates. Also the spinning toolsneeded to make these geometric shapes are quite expensive and difficultto make, and have a relatively short useful life because of breakage orthe like, which further adds to the cost of making cavities having thesegeometric shapes.

SUMMARY OF THE INVENTION

The difficulty and cost of making optical substrates including one ormore patterns of optical elements having at least two surfaces that cometogether to form a ridge and are quite small relative to the length andwidth of the optical substrates are substantially reduced by using atool to cut or form cavities of such patterns of optical element shapesin a substrate without rotating the tool or substrate during the cuttingor forming process, and thereafter using the substrate to form theoptical substrates having the optical elements on or in at least onesurface of the optical substrates corresponding to the cavities in thesubstrate.

The tool that is used to cut or form the optical element shaped cavitiesin a substrate may either be perpendicular or nonperpendicular to thepath of the tool during the cutting or forming process. Also the toolmay either have a symmetrical or nonsymmetrical cutting or forming tipor have a symmetrical or nonsymmetrical profile on either side of theplane of the cutting or forming path (cut move) of the tool. If the toolhas a symmetrical profile on either side of the plane of the cut move ofthe tool, at least the two surfaces of the cavities that come togetherto form a ridge during the cutting or forming process are symmetricalsurfaces, whereas if the tool has a nonsymmetrical profile on eitherside of the plane of the tool cutting or forming path, at least the twosurfaces of the cavities that come together to form a ridge during thecutting or forming process are nonsymmetrical surfaces. Moreover atleast some of the cavities may have one flat surface and one curvedsurface or two curved surfaces. Also at least some of the cavities mayonly have two surfaces, one of which may be flat and the other curved.Alternatively, both surfaces may be curved.

During the cutting or forming process, one or both the tool andsubstrate may move relative to each other without rotating relative toeach other. The substrate or tool is positioned to produce a specificplacement for each cavity prior to each cutting or forming process. Alsothe substrate or tool may be rotated relative to each other prior tocutting or forming at least some of the cavities to produce a differentorientation for these cavities. Other cavities that have the sameorientation may be cut or formed consecutively so that the substrate ortool need only be rotated between the cutting or forming of some of thecavities.

The tool may have a cutting or forming edge that lies in a planeparallel to a vector normal to the surface of the substrate or parallelto the path of the tool during the cutting or forming process. Also thetool may move into the substrate along either a nonlinear path, whichmay be a curve, or a linear path, which may change directions atdiscrete points during the cutting or forming process.

The surface of the substrate in which the cavities are cut or formed mayeither be flat, curved, conical or cylindrical. Also at least some ofthe cavities may vary in size, shape, angle, rotation, orientation,density, depth, height, type or placement, and may overlap, intersect orinterlock with other cavities. Further, at least some of the cavitiesmay vary randomly in the substrate, and at least some of the ridges maygenerally be in the same direction, and may be curved, segmented orhybrid in shape.

Either the substrate itself or a deposition or mirror copy of thesubstrate may be used to form such optical substrates either by molding,thermoforming, hot stamping, embossing, extrusion, or radiation curingor the like. The optical substrates that are formed using the substrate(or a deposition or mirror copy of the substrate) formed in accordancewith the present invention may have a light entrance surface and anopposite light exit surface with at least some of the optical elementsbeing formed on at least one of the surfaces having a ridge angle ofbetween 60 and 80 degrees or between 85 and 95 degrees. Moreover, theoptical elements may substantially cover at least 90% of at least onesurface of the optical substrates.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter more fully described andparticularly pointed out in the claims, the following description andannexed drawings setting forth in detail certain illustrativeembodiments of the invention, these being indicative, however, of butseveral of the various ways in which the principles of the invention maybe employed.

BRIEF DESCRIPTION OF THE DRAWINGS

In the annexed drawings:

FIG. 1 is a schematic side elevation view of one form of lightredirecting film system in accordance with the present invention;

FIG. 2 is an enlarged fragmentary side elevation view of a portion ofthe backlight and light redirecting film system of FIG. 1;

FIGS. 3 and 4 are schematic side elevation views of other forms of lightredirecting film systems of the present invention;

FIGS. 5-20 are schematic perspective or plan views showing differentpatterns of individual optical elements on light redirecting films ofthe present invention;

FIGS. 5 a-5 n are schematic perspective views of different geometricshapes that the individual optical elements on the light redirectingfilms may take;

FIG. 21 is a schematic perspective view of a light redirecting filmhaving optical grooves extending across the film in a curved patternfacing a corner of the film;

FIG. 22 is a top plan view of a light redirecting film having a patternof optical grooves extending across the film facing a midpoint on oneedge of the film that decreases in curvature as the distance from theone edge increases;

FIG. 23 is an end elevation view of the light redirecting film of FIG.22 as seen from the left end thereof;

FIG. 24 is a side elevation view of the light redirecting film of FIG.22;

FIGS. 25 and 26 are enlarged schematic fragmentary plan views of asurface area of a backlight/light emitting panel assembly showingvarious forms of optical deformities formed on or in a surface of thebacklight;

FIGS. 27 and 28 are enlarged longitudinal sections through one of theoptical deformities of FIGS. 25 and 26, respectively;

FIGS. 29 and 30 are enlarged schematic longitudinal sections throughother forms of optical deformities formed on or in a surface of abacklight;

FIGS. 31-39 are enlarged schematic perspective views of backlightsurface areas containing various patterns of individual opticaldeformities of other well defined shapes;

FIG. 40 is an enlarged schematic longitudinal section through anotherform of optical deformity formed on or in a surface of a backlight;

FIGS. 41 and 42 are enlarged schematic top plan views of backlightsurface areas containing optical deformities similar in shape to thoseshown in FIGS. 37 and 38 arranged in a plurality of straight rows alongthe length and width of the surface areas;

FIGS. 43 and 44 are enlarged schematic top plan views of backlightsurface areas containing optical deformities also similar in shape tothose shown in FIGS. 37 and 38 arranged in staggered rows along thelength of the surface areas;

FIGS. 45 and 46 are enlarged schematic top plan views of backlightsurface areas containing a random or variable pattern of different sizedoptical deformities on the surface areas;

FIG. 47 is an enlarged schematic perspective view of a backlight surfacearea showing optical deformities increasing in size as the distance ofthe deformities from the light input surface increases or intensity ofthe light increases along the length of the surface area;

FIGS. 48 and 49 are schematic perspective views showing differentangular orientations of the optical deformities along the length andwidth of a backlight surface area;

FIGS. 50 and 51 are enlarged perspective views schematically showing howexemplary light rays emitted from a focused light source are reflectedor refracted by different individual optical deformities of well definedshapes of a backlight surface area;

FIGS. 52, 53, 57-60, 63 and 64 are schematic perspective views showingtools used to cut or form optical element shaped cavities of the desiredsize, shape, angle, rotation, orientation, density, depth, height, typeand placement in flat, curved or cylindrical substrates wherein thecavities have at least two surfaces that come together to form a ridge;

FIG. 54 is an enlarged schematic fragmentary elevation view showing atool tip having at least one cutting or forming edge that is parallel tothe tool cross path to form at least one flat surface in a cavity duringthe cutting or forming process;

FIGS. 55 a-55 d are enlarged schematic perspective views of differentrepresentative geometric shapes of the individual cavities that may becut or formed in the substrates;

FIG. 56 a is a schematic front elevation view of a tool having a cuttingor forming tip that is symmetrical about both the tool axis and the toolcut path;

FIG. 56 b is a schematic front elevation view of a tool having a cuttingor forming tip that is not symmetrical about the tool axis but issymmetrical about the tool cut path;

FIGS. 61 a-61 c are schematic illustrations of representative non-lineartool cross paths;

FIGS. 62 a-62 c are schematic illustrations of representative lineartool cross paths; and

FIGS. 65-67 are schematic elevation views showing production toolingmade from the substrates containing the cavities or a deposition ormirror copy of the substrates used to form optical substrates bymolding, thermoforming, hot stamping, embossing, extrusion and/orradiation curing and the like.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 and 2 schematically show one form of light redirecting filmsystem 1 in accordance with this invention including a light redirectingfilm 2 that redistributes more of the light emitted by a backlight BL orother light source toward a direction more normal to the surface of thefilm. Film 2 may be used to redistribute light within a desired viewingangle from almost any light source for lighting, for example, a displayD such as a liquid crystal display, used in laptop computers, wordprocessors, avionic displays, cell phones, PDAs and the like, to makethe displays brighter. The liquid crystal display can be any typeincluding a transmissive liquid crystal display as schematically shownin FIGS. 1 and 2, a reflective liquid crystal display as schematicallyshown in FIG. 3 and a transflective liquid crystal display asschematically shown in FIG. 4.

The reflective liquid crystal display D shown in FIG. 3 includes a backreflector 40 adjacent the back side for reflecting ambient lightentering the display back out the display to increase the brightness ofthe display. The light redirecting film 2 of the present invention isplaced adjacent the top of the reflective liquid crystal display toredirect ambient light (or light from a front light) into the displaytoward a direction more normal to the plane of the film for reflectionback out by the back reflector within a desired viewing angle toincrease the brightness of the display. Light redirecting film 2 may beattached to, laminated to or otherwise held in place against the top ofthe liquid crystal display.

The transflective liquid crystal display D shown in FIG. 4 includes atransreflector T placed between the display and a backlight BL forreflecting ambient light entering the front of the display back out thedisplay to increase the brightness of the display in a lightedenvironment, and for transmitting light from the backlight through thetransreflector and out the display to illuminate the display in a darkenvironment. In this embodiment the light redirecting film 2 may eitherbe placed adjacent the top of the display or adjacent the bottom of thedisplay or both as schematically shown in FIG. 4 for redirecting orredistributing ambient light and/or light from the backlight more normalto the plane of the film to make the light ray output distribution moreacceptable to travel through the display to increase the brightness ofthe display.

Light redirecting film 2 comprises a thin transparent film or substrate8 having a pattern of discrete individual optical elements 5 of welldefined shape on the light exit surface 6 of the film for refracting theincident light distribution such that the distribution of the lightexiting the film is in a direction more normal to the surface of thefilm.

Each of the individual optical elements 5 has a width and length manytimes smaller than the width and length of the film, and may be formedby depressions in or projections on the exit surface of the film. Theseindividual optical elements 5 include at least one sloping surface forrefracting the incident light toward the direction normal to the lightexit surface. FIG. 5 shows one pattern of individual optical elements 5on a film 2. These optical elements may take many different shapes. Forexample, FIG. 5 a shows a non-prismatic optical element 5 having a totalof two surfaces 10, 12, both of which are sloping. One of the surfaces10 shown in FIG. 5 a is planar or flat whereas the other surface 12 iscurved. Moreover, both surfaces 10, 12 intersect each other and alsointersect the surface of the film. Alternatively, both surfaces 10, 12of the individual optical elements may be curved as schematically shownin FIG. 5 b.

Alternatively, the optical elements 5 may each have only one surfacethat is curved and sloping and intersects the film. FIG. 5 c shows onesuch optical element 5 in the shape of a cone 13, whereas FIG. 5 d showsanother such optical element having a semispherical or dome shape 14.Also, such optical elements may have more than one sloping surfaceintersecting the film.

FIG. 5 e shows an optical element 5 having a total of three surfaces,all of which intersect the film and intersect each other. Two of thesurfaces 15 and 16 are curved, whereas the third surface 17 is planar.

FIG. 5 f shows an optical element 5 in the shape of a pyramid 18 withfour triangular shaped sides 19 that intersect each other and intersectthe film. The sides 19 of the pyramid 18 may all be of the same size andshape as shown in FIG. 5 f, or the sides 19 of the pyramids 18 may bestretched so the sides have different perimeter shapes as shown in FIG.5 g. Also, the optical elements 5 may have any number of planar slopingsides. FIG. 5 h shows an optical element 5 with four planar slopingsides 20, whereas FIG. 5 i shows an optical element 5 with eight planarsloping sides 20.

The individual optical elements 5 may also have more than one curved andmore than one planar sloping surface, all intersecting the film. FIG. 5j shows an optical element 5 having a pair of intersecting oppositelysloping planar sides 22 and oppositely rounded or curved ends or sides23. Further, the sloping planar sides 22 and curved ends or sides 23 mayhave different angled slopes as shown in FIGS. 5 k and 5 l. Moreover,the optical elements 5 may have at least one curved surface that doesnot intersect the film. One such optical element 5 is shown in FIG. 5 mwhich includes a pair of oppositely sloping planar sides 22 andoppositely rounded or curved ends or sides 23 and a rounded or curvedtop 24 intersecting the oppositely sloping sides and oppositely roundedends. Further, the optical elements 5 may be curved along their lengthas shown in FIG. 5 n.

Providing the individual optical elements 5 with a combination of planarand curved surfaces redirects or redistributes a larger viewing areathan is possible with a grooved film. Also, the curvature of thesurfaces, or the ratio of the curved area to the planar area of theindividual optical elements may be varied to tailor the light outputdistribution of the film to customize the viewing area of a displaydevice used in conjunction with the film.

The light entrance surface 7 of the film 2 may have an optical coating25 (see FIG. 2) such as an antireflective coating, a reflectivepolarizer, a retardation coating or a polarizer. Also, a matte ordiffuse texture may be provided on the light entrance surface 7depending on the visual appearance desired. A matte finish produces asofter image but is not as bright. The combination of planar and curvedsurfaces of the individual optical elements 5 of the present inventionmay be configured to redirect some of the light rays impinging thereonin different directions to produce a softer image without the need foran additional diffuser or matte finish on the entrance surface of thefilm.

The individual optical elements 5 of the light redirecting film 2 alsodesirably overlap each other in a staggered, interlocked and/orintersecting configuration, creating an optical structure with excellentsurface area coverage. FIGS. 6, 7, 13 and 15, for example, show opticalelements 5 staggered with respect to each other; FIGS. 8-10 show theoptical elements 5 intersecting each other; and FIGS. 11 and 12 show theoptical elements 5 intersecting each other.

Moreover, the slope angle, density, position, orientation, height ordepth, shape, and/or size of the optical elements 5 of the lightredirecting film 2 may be matched or tuned to the particular lightoutput distribution of a backlight BL or other light source to accountfor variations in the distribution of light emitted by the backlight inorder to redistribute more of the light emitted by the backlight withina desired viewing angle. For example, the angle that the slopingsurfaces (e.g., surfaces 10, 12) of the optical elements 5 make with thesurface of the light redirecting film 2 may be varied as the distancefrom the backlight BL from a light source 26 increases to account forthe way the backlight emits light rays R at different angles as thedistance from the light source increases as schematically shown in FIG.2. Also, the backlight BL itself may be designed to emit more of thelight rays at lower angles to increase the amount of light emitted bythe backlight and rely on the light redirecting film 2 to redistributemore of the emitted light within a desired viewing angle. In this waythe individual optical elements 5 of the light redirecting film 2 may beselected to work in conjunction with the optical deformations of thebacklight to produce an optimized output light ray angle distributionfrom the system.

FIGS. 2, 5 and 9 show different patterns of individual optical elements5 all of the same height or depth, whereas FIGS. 7, 8, 10, 13 and 14show different patterns of individual optical elements 5 of differentshapes, sizes and height or depth.

The individual optical elements 5 may also be randomized on the film 2as schematically shown in FIGS. 16 and 17 in such a way as to eliminateany interference with the pixel spacing of a liquid crystal display.This eliminates the need for optical diffuser layers 30 shown in FIGS. 1and 2 to defeat moiré and similar effects. Moreover, at least some ofthe individual optical elements 5 may be arranged in groupings 32 acrossthe film, with at least some of the optical elements 5 in each groupinghaving a different size or shape characteristic that collectivelyproduce an average size or shape characteristic for each of thegroupings that varies across the film as schematically shown in FIGS. 7,13 and 15 to obtain characteristic values beyond machining tolerances todefeat moiré and interference effects with the liquid crystal displaypixel spacing. For example, at least some of the optical elements 5 ineach grouping 32 may have a different depth or height that collectivelyproduce an average depth or height characteristic for each grouping thatvaries across the film. Also, at least some of the optical elements ineach grouping may have a different slope angle that collectively producean average slope angle for each grouping that varies across the film.Further, at least one sloping surface of the individual optical elementsin each grouping may have a different width or length that collectivelyproduce an average width or length characteristic in each grouping thatvaries across the film.

Where the individual optical elements 5 include a combination of planarand curved surfaces 10, 12, the curvature of the curved surfaces 12, orthe ratio of the curved area to the planar area of the individualoptical elements as well as the perimeter shapes of the curved andplanar surfaces may be varied to tailor the light output distribution ofthe film. In addition, the curvature of the curved surfaces, or theratio of the curved area to the planar area of the individual opticalelements may be varied to redirect more or less light that is travelingin a plane that would be parallel to the grooves of a prismatic orlenticular grooved film, partially or completely replacing the need fora second layer of light redirecting film. Also, at least some of theindividual optical elements may be oriented at different angles relativeto each other as schematically shown in FIGS. 13 and 16 to redistributemore of the light emitted by a light source along two different axes ina direction more normal to the surface of the film, partially orcompletely replacing the need for a second layer of light redirectingfilm. However, it will be appreciated that two layers of such lightredirecting film each having the same or different patterns ofindividual optical elements 5 thereon may be placed between a lightsource and viewing area with the layers rotated 90 degrees (or otherangles greater than 0 degrees and less than 90 degrees) with respect toeach other so that the individual optical elements on the respectivefilm layers redistribute more of the light emitted by a light sourcetraveling in different planar directions in a direction more normal tothe surface of the respective films.

Also, the light redirecting film 2 may have a pattern of opticalelements 5 that varies at different locations on the film asschematically shown in FIG. 15 to redistribute the light ray outputdistribution from different locations of a backlight or other lightsource to redistribute the light ray output distribution from thedifferent locations toward a direction normal to the film.

Further, the properties and pattern of the optical elements of the lightredirecting film may be customized to optimize the light redirectingfilm for different types of light sources which emit different lightdistributions, for example, one pattern for single bulb laptops, anotherpattern for double bulb flat panel displays, and so on.

FIG. 17 shows the optical elements 5 arranged in a radial pattern fromthe outside edges of the film 2 toward the center to redistribute thelight ray output distribution of a backlight BL that receives light fromcold cathode fluorescent lamps 26 along all four side edges of thebacklight.

FIG. 18 shows the optical elements 5 arranged in a pattern of angledgroupings 32 across the film 2 that are tailored to redistribute thelight ray output distribution of a backlight BL that receives light fromone cold cathode fluorescent lamp 26 or a plurality of light emittingdiodes 26 along one input edge of the backlight.

FIG. 19 shows the optical elements 5 arranged in a radial type patternfacing a corner of the film 2 to redistribute the light ray outputdistribution of a backlight BL that is corner lit by a light emittingdiode 26. FIG. 20 shows the optical elements 5 arranged in a radial typepattern facing a midpoint on one input edge of the film 2 toredistribute the light ray output distribution of a backlight BL that islighted at a midpoint of one input edge of the backlight by a singlelight emitting diode 26.

FIG. 21 shows a light redirecting film 2 having optical grooves 35extending across the film in a curved pattern facing a corner of thefilm to redistribute the light ray output distribution of a backlight BLthat is corner lit by a light emitting diode 26, whereas FIGS. 22-24show a light redirecting film 2 having a pattern of optical grooves 35extending across the film facing a midpoint along one edge of the filmthat decreases in curvature as the distance from the one edge increasesto redistribute the light ray output distribution of a backlight BL thatis edge lit by a light emitting diode 26 at a midpoint of one input edgeof the backlight.

Where the light redirecting film 2 has a pattern 40 of optical elements5 thereon that varies along the length of the film, a roll 41 of thefilm 2 may be provided having a repeating pattern of optical elementsthereon as schematically shown in FIG. 15 to permit a selected area ofthe pattern that best suits a particular application to be die cut fromthe roll of film.

The backlight BL may be substantially flat, or curved, or may be asingle layer or multi-layers, and may have different thicknesses andshapes as desired. Moreover, the backlight may be flexible or rigid, andbe made of a variety of compounds. Further, the backlight may be hollow,filled with liquid, air, or be solid, and may have holes or ridges.

Also, the light source 26 may be of any suitable type including, forexample, an arc lamp, an incandescent bulb which may also be colored,filtered or painted, a lens end bulb, a line light, a halogen lamp, alight emitting diode (LED), a chip from an LED, a neon bulb, a coldcathode fluorescent lamp, a fiber optic light pipe transmitting from aremote source, a laser or laser diode, or any other suitable lightsource. Additionally, the light source 26 may be a multiple colored LED,or a combination of multiple colored radiation sources in order toprovide a desired colored or white light output distribution. Forexample, a plurality of colored lights such as LEDs of different colors(e.g., red, blue, green) or a single LED with multiple color chips maybe employed to create white light or any other colored light outputdistribution by varying the intensities of each individual coloredlight.

A pattern of optical deformities may be provided on one or both sides ofthe backlight BL or on one or more selected areas on one or both sidesof the backlight as desired. As used herein, the term opticaldeformities means any change in the shape or geometry of a surfaceand/or coating or surface treatment that causes a portion of the lightto be emitted from the backlight. These deformities can be produced in avariety of manners, for example, by providing a painted pattern, anetched pattern, machined pattern, a printed pattern, a hot stamppattern, or a molded pattern or the like on selected areas of thebacklight. An ink or print pattern may be applied for example by padprinting, silk printing, inkjet, heat transfer film process or the like.The deformities may also be printed on a sheet or film which is used toapply the deformities to the backlight. This sheet or film may become apermanent part of the backlight for example by attaching or otherwisepositioning the sheet or film against one or both sides of the backlightin order to produce a desired effect.

By varying the density, opaqueness or translucence, shape, depth, color,area, index of refraction or type of deformities on or in an area orareas of the backlight, the light output of the backlight can becontrolled. The deformities may be used to control the percent of lightoutput from a light emitting area of the backlight. For example, lessand/or smaller size deformities may be placed on surface areas whereless light output is wanted. Conversely, a greater percentage of and/orlarger deformities may be placed on surface areas of the backlight wheregreater light output is desired.

Varying the percentages and/or size of deformities in different areas ofthe backlight is necessary in order to provide a substantially uniformlight output distribution. For example, the amount of light travelingthrough the backlight will ordinarily be greater in areas closer to thelight source than in other areas further removed from the light source.A pattern of deformities may be used to adjust for the light varianceswithin the backlight, for example, by providing a denser concentrationof deformities with increased distance from the light source therebyresulting in a more uniform light output distribution from thebacklight.

The deformities may also be used to control the output ray angledistribution from the backlight to suit a particular application. Forexample, if the backlight is used to backlight a liquid crystal display,the light output will be more efficient if the deformities (or a lightredirecting film 2 is used in combination with the backlight) direct thelight rays emitted by the backlight at predetermined ray angles suchthat they will pass through the liquid crystal display with low loss.Additionally, the pattern of optical deformities may be used to adjustfor light output variances attributed to light extractions of thebacklight. The pattern of optical deformities may be printed on thebacklight surface areas utilizing a wide spectrum of paints, inks,coatings, epoxies or the like, ranging from glossy to opaque or both,and may employ half-tone separation techniques to vary the deformitycoverage. Moreover, the pattern of optical deformities may be multiplelayers or vary in index of refraction.

Print patterns of optical deformities may vary in shapes such as dots,squares, diamonds, ellipses, stars, random shapes, and the like. Also,print patterns of sixty lines per inch or finer are desirably employed.This makes the deformities or shapes in the print patterns nearlyinvisible to the human eye in a particular application, therebyeliminating the detection of gradient or banding lines that are commonto light extracting patterns utilizing larger elements. Additionally,the deformities may vary in shape and/or size along the length and/orwidth of the backlight. Also, a random placement pattern of thedeformities may be utilized throughout the length and/or width of thebacklight. The deformities may have shapes or a pattern with no specificangles to reduce moiré or other interference effects. Examples ofmethods to create these random patterns are printing a pattern of shapesusing stochastic print pattern techniques, frequency modulated half tonepatterns, or random dot half tones. Moreover, the deformities may becolored in order to effect color correction in the backlight. The colorof the deformities may also vary throughout the backlight, for example,to provide different colors for the same or different light outputareas.

In addition to or in lieu of the patterns of optical deformities, otheroptical deformities including prismatic or lenticular grooves or crossgrooves, or depressions or raised surfaces of various shapes using morecomplex shapes in a mold pattern may be molded, etched, stamped,thermoformed, hot stamped or the like into or on one or more surfaceareas of the backlight. The prismatic or lenticular surfaces,depressions or raised surfaces will cause a portion of the light rayscontacted thereby to be emitted from the backlight. Also, the angles ofthe prisms, depressions or other surfaces may be varied to direct thelight in different directions to produce a desired light outputdistribution or effect. Moreover, the reflective or refractive surfacesmay have shapes or a pattern with no specific angles to reduce moiré orother interference effects.

A back reflector 40 may be attached or positioned against one side ofthe backlight BL as schematically shown in FIGS. 1 and 2 in order toimprove light output efficiency of the backlight by reflecting the lightemitted from that side back through the backlight for emission throughthe opposite side. Additionally, a pattern of optical deformities 50 maybe provided on one or both sides of the backlight as schematically shownin FIGS. 1 and 2 in order to change the path of the light so that theinternal critical angle is exceeded and a portion of the light isemitted from one or both sides of the backlight.

FIGS. 25-28 show optical deformities 50 which may either be individualprojections 51 on the respective backlight surface areas 52 orindividual depressions 53 in such surface areas. In either case, each ofthese optical deformities 50 has a well defined shape including areflective or refractive surface 54 that intersects the respectivebacklight surface area 52 at one edge 55 and has a uniform slopethroughout its length for more precisely controlling the emission oflight by each of the deformities. Along a peripheral edge portion 56 ofeach reflective/refractive surface 54 is an end wall 57 of eachdeformity 50 that intersects the respective panel surface area 52 at agreater included angle I than the included angle I′ between thereflective/refractive surfaces 54 and the panel surface area 52 (seeFIGS. 27 and 28) to minimize the projected surface area of the end wallson the panel surface area. This allows more deformities 50 to be placedon or in the panel surface areas than would otherwise be possible if theprojected surface areas of the end walls 57 were substantially the sameas or greater than the projected surface areas of thereflective/refractive surfaces 54.

In FIGS. 25 and 26 the peripheral edge portions 56 of thereflective/refractive surfaces 54 and associated end walls 57 are curvedin the transverse direction. Also in FIGS. 27 and 28 the end walls 57 ofthe deformities 50 are shown extending substantially perpendicular tothe reflective/refractive surfaces 54 of the deformities. Alternatively,such end walls 57 may extend substantially perpendicular to the panelsurface areas 52 as schematically shown in FIGS. 29 and 30. Thisvirtually eliminates any projected surface area of the end walls 57 onthe panel surface areas 52 whereby the density of the deformities on thepanel surface areas may be even further increased.

The optical deformities may also be of other well defined shapes toobtain a desired light output distribution from a panel surface area.FIG. 31 shows individual light extracting deformities 58 on a panelsurface area 52 each including a generally planar, rectangularreflective/refractive surface 59 and associated end wall 60 of a uniformslope throughout their length and width and generally planar side walls61. Alternatively, the deformities 58′ may have rounded or curved sidewalls 62 as schematically shown in FIG. 32.

FIG. 33 shows individual light extracting deformities 63 on a panelsurface area 52 each including a planar, sloping triangular shapedreflective/refractive surface 64 and associated planar, generallytriangularly shaped side walls or end walls 65. FIG. 34 shows individuallight extracting deformities 66 each including a planar slopingreflective/refractive surface 67 having angled peripheral edge portions68 and associated angled end and side walls 69 and 70.

FIG. 35 shows individual light extracting deformities 71 which aregenerally conically shaped, whereas FIG. 36 shows individual lightextracting deformities 72 each including a rounded reflective/refractivesurface 73 and rounded end walls 74 and rounded or curved side walls 75all blended together. These additional surfaces will reflect or refractother light rays impinging thereon in different directions to spreadlight across the backlight/panel member BL to provide a more uniformdistribution of light emitted from the panel member.

Regardless of the particular shape of the reflective/refractive surfacesand end and side walls of the individual deformities, such deformitiesmay also include planar surfaces intersecting the reflective/refractivesurfaces and end and/or side walls in parallel spaced relation to thepanel surface areas 52. FIGS. 37-39 show deformities 76, 77 and 78 inthe form of individual projections on a panel surface area havingrepresentative shapes similar to those shown in FIGS. 31, 32 and 35,respectively, except that each deformity is intersected by a planarsurface 79 in parallel spaced relation to the panel surface area 52. Inlike manner, FIG. 40 shows one of a multitude of deformities 80 in theform of individual depressions 81 in a panel surface area 52 eachintersected by a planar surface 79 in parallel spaced relation to thegeneral planar surface of the panel surface area 52. Any light rays thatimpinge on such planar surfaces 79 at internal angles less than thecritical angle for emission of light from the panel surface area 52 willbe internally reflected by the planar surfaces 79, whereas any lightrays impinging on such planar surfaces 79 at internal angles greaterthan the critical angle will be emitted by the planar surfaces withminimal optical discontinuities, as schematically shown in FIG. 40.

Where the deformities are projections on the panel surface area 52, thereflective/refractive surfaces extend at an angle away from the panel ina direction generally opposite to that in which the light rays from thelight source 26 travel through the panel as schematically shown in FIGS.27 and 29. Where the deformities are depressions in the panel surfacearea, the reflective/refractive surfaces extend at an angle into thepanel in the same general direction in which the light rays from thelight source 26 travel through the panel member as schematically shownin FIGS. 28 and 30.

Regardless of whether the deformities are projections or depressions onor in the panel surface areas 52, the slopes of the lightreflective/refractive surfaces of the deformities may be varied to causethe light rays impinging thereon to be either refracted out of the lightemitting panel or reflected back through the panel and emitted out theopposite side of the panel which may be etched to diffuse the lightemitted therefrom or covered by a light redirecting film 2 to produce adesired effect. Also, the pattern of optical deformities on the panelsurface area may be uniform or variable as desired to obtain a desiredlight output distribution from the panel surface areas. FIGS. 41 and 42show deformities 76 and 77 similar in shape to those shown in FIGS. 37and 38 arranged in a plurality of generally straight uniformly spacedapart rows along the length and width of a panel surface area 52,whereas FIGS. 43 and 44 show such deformities 76 and 77 arranged instaggered rows that overlap each other along the length of a panelsurface area.

Also, the size, including the width, length and depth or height as wellas the angular orientation and position of the optical deformities mayvary along the length and/or width of any given panel surface area toobtain a desired light output distribution from the panel surface area.FIGS. 45 and 46 show a random or variable pattern of different sizedeformities 58 and 58′ similar in shape to those shown in FIGS. 31 and32, respectively, arranged in staggered rows on a panel surface area 52,whereas FIG. 47 shows deformities 77 similar in shape to those shown inFIG. 38 increasing in size as the distance of the deformities from thelight source increases or intensity of the light decreases along thelength and/or width of the panel surface area. The deformities 58 and58′ are shown in FIGS. 45 and 46 arranged in clusters 82 across thepanel surface, with at least some of the deformities in each clusterhaving a different size or shape characteristic that collectivelyproduce an average size or shape characteristic for each of the clustersthat varies across the panel surface. For example, at least some of thedeformities in each of the clusters may have a different depth or heightor different slope or orientation that collectively produce an averagedepth or height characteristic or average slope or orientation of thesloping surface that varies across the panel surface. Likewise at leastsome of the deformities in each of the clusters may have a differentwidth or length that collectively produce an average width or lengthcharacteristic that varies across the panel surface. This allows one toobtain a desired size or shape characteristic beyond machinerytolerances, and also defeats moiré and interference effects.

FIGS. 48 and 49 schematically show different angular orientations ofoptical deformities 85 of any desired shape along the length and widthof a panel surface area 52. In FIG. 48 the deformities are arranged instraight rows 86 along the length of the panel surface area but thedeformities in each of the rows are oriented to face the light source 26so that all of the deformities are substantially in line with the lightrays being emitted from the light source. In FIG. 49 the deformities 85are also oriented to face the light source 26 similar to FIG. 48. Inaddition, the rows 87 of deformities in FIG. 49 are in substantialradial alignment with the light source 26.

FIGS. 50 and 51 schematically show how exemplary light rays 90 emittedfrom a focused light source 26 insert molded or cast within a lighttransition area 91 of a light emitting panel assembly BL in accordancewith this invention are reflected during their travel through the lightemitting panel member 92 until they impinge upon individual lightextracting deformities 50, 77 of well defined shapes on or in a panelsurface area 52 causing more of the light rays to be reflected orrefracted out of one side 93 of the panel member than the other side 94.In FIG. 50 the exemplary light rays 90 are shown being reflected by thereflective/refractive surfaces 54 of the deformities 50 in the samegeneral direction out through the same side 93 of the panel member,whereas in FIG. 51 the light rays 90 are shown being scattered indifferent directions within the panel member 92 by the rounded sidewalls 62 of the deformities 77 before the light rays arereflected/refracted out of the same side 93 of the panel member. Such apattern of individual light extracting deformities of well definedshapes in accordance with the present invention can cause 60 to 70% ormore of the light received through the input edge 95 of the panel memberto be emitted from the same side of the panel member.

From the foregoing, it will be apparent that the light redirecting filmsof the present invention redistribute more of the light emitted by abacklight or other light source toward a direction more normal to theplane of the films. Also, the light redirecting films and backlights ofthe present invention may be tailored or tuned to each other to providea system in which the individual optical elements of the lightredirecting films work in conjunction with the optical deformities ofthe backlights to produce an optimized output light ray angledistribution from the system.

Predetermined patterns of individual optical elements (including opticaldeformities) of well defined shape may be formed on or in films,components or wave guides (hereafter optical substrates) using knownmanufacturing methods. One such known manufacturing method involvescutting or forming a pattern of cavities of such optical element shapesin a flat sheet or plate using a milling or laser cutter and using thecut or formed optical element shapes in the sheet or plate to form acorresponding pattern of optical elements on or in the opticalsubstrates. A drawback to this method is the difficulty and expense ofcutting or forming cavities of certain types of optical element shapesincluding particularly those having at least two surfaces that cometogether to form a ridge and are quite small relative to the length andwidth of the optical substrates in which the optical elements aresubsequently formed. Also the spinning tools needed to make thesegeometric shapes are quite expensive and difficult to make, and have arelatively short useful life because of breakage or the like, whichfurther adds to the cost of making cavities having these geometricshapes.

The difficulty and cost of making cavities having these geometric shapesmay be substantially reduced in accordance with the present invention byusing a tool to cut or form such patterns of optical element shapedcavities in a substrate without rotating the tool or substrate duringthe cutting or forming process.

FIGS. 52 and 53 show one such tool 100 for cutting or forming suchcavities 101 and 102, respectively, in a substrate 103 that is notperpendicular to the cutting or forming path (cut move) of the tool. Oneor both the tool 100 and substrate 103 may be moved either in a linearor nonlinear cross path during the cut move. In the case of FIG. 52 thecut move 104 is perpendicular to the axis of the tool, whereas in thecase of FIG. 53 the cut move 105 is parallel to the tool axis. Also inFIG. 52 (as well as in FIG. 54) the tool tip 106 (which may be a diamondtip or a tip made of some other suitable cutting or forming material)has at least one cutting or forming edge 107 that is parallel to thetool cross path (shown in phantom lines 108 in FIG. 54) in order tocut/form a cavity 101 such as shown in FIG. 52 (and also in FIG. 55 a)having at least one flat surface 109 and at least one curved surface 110that come together to form a ridge 111 and are quite small relative tothe length and width of the optical substrates in which the opticalelements are subsequently formed. In FIG. 53, on the other hand, thetool 100 is provided with a different shaped tip 115 that is shaped toform a cavity 102 having at least two curved surfaces 116, 117 that cometogether to form a ridge 118 and that may either be symmetrical to oneanother as shown in FIG. 55 b or nonsymmetrical to one another as shownin FIG. 55 c depending on whether or not the tool tip has a symmetricalprofile on either side of the plane of the cut move 105 of the tool.

The substrate 103 or tool 100 or both is positioned to produce aspecific placement for each cavity prior to each cutting or formingprocess. For example, the substrate or tool (or both) may be positionedso that at least some of the ridges of at least some of the cavities aregenerally in the same direction for producing optical elements havingridges 119 generally in the same direction as shown, for example, inFIGS. 5, 8-11, 31, 32, 45-47 and 50. Also the substrate or tool may bepositioned so that at least some of the cavities overlap, intersect orinterlock with other cavities so that the correspondingly shaped opticalelements produced thereby also overlap, intersect or interlock withother optical elements as shown, for example, in FIGS. 5, 6-11 and 13.Moreover, the optical elements may cover at least 90% of at least onesurface of the optical substrates.

The optical substrates that are formed using the substrates made inaccordance with the present invention may have a light entrance surfaceand a light exit surface with at least some of the optical elementsformed on at least one of the surfaces having a ridge angle RA (see FIG.2) of between 60 degrees and 80 degrees or between 85 degrees and 95degrees.

The cavities that are cut or formed in the substrate during the cuttingor forming process may also vary in size, shape, angle, rotation,orientation, depth, height, type and/or placement to form opticalelements on or in the optical substrates that correspondingly vary.Likewise, at least some of the cavities may be cut or formed randomly inthe substrate to produce at least some optical elements on or in theoptical substrates that also vary randomly.

In order to produce a different orientation for at least some of thecavities (to produce for example optical substrates having opticalelements with the different orientations shown in FIGS. 13, 16, 17-20,48 and 49), the substrate or tool is rotated prior to cutting or formingthese cavities. However, where at least some of the optical elementsalso have the same orientation as shown in these figures, the cavitiesfor forming these optical elements may be cut or formed consecutively sothat the substrate or tool need only be positioned between the cuttingor forming of at least some of the cavities.

In FIGS. 57 and 58 the cut move 120 of the tool 100 is in a planeperpendicular to the substrate 103. Also in FIG. 57 the cut move isparallel to the tool axis (because the tool axis is perpendicular to thesubstrate) whereas in FIG. 58 the cut move is at an angle to the toolaxis (because the tool axis is at an angle relative to the substrate).

In FIG. 57 the tool 100 has a cutting or forming tip 121 that isnonsymmetrical about the tool axis which produces nonsymmetricalcavities 102 in the substrate having at least one curved surface 117 onone side of the cavity that is larger than at least one other curvedsurface 116 on the other side of the cavity, similar to the cavity shownin FIG. 55( c).

In FIG. 58 the tool tip 122 is symmetrical with respect to the toolaxis. However, because the tool axis is at an angle to the substrate andthe cut move 120 is in a plane perpendicular to the substrate, the tooltip of FIG. 58 also produces nonsymmetrical cavities having at least twocurved surfaces 116 and 117, one of which is larger than the other.

FIG. 59 shows a tool 100 similar to that shown in FIG. 57 except thatthe tool tip 123 is symmetrical about the tool axis. Also FIG. 59 showsthat the tool 100 may be fixed and the substrate 103 may move in adirection parallel to the tool axis and in the tool cross path directionduring the cutting or forming process. Likewise, the substrate may bepositioned to produce a specific placement for each cavity 102 prior toeach cutting or forming process, and may also be rotated to produce adifferent orientation for at least some of the cavities prior to cuttingor forming at least some of the cavities.

FIG. 60 shows a tool 100 that is not perpendicular to the substrate 103.However, the cut move 125 is perpendicular to the substrate. Also inFIG. 60 the tool tip 126 is not symmetrical to the tool axis. However,the plane of the cut move 125 bisects the tool tip so the tool tip 126is symmetrical to the cut move as schematically shown in FIG. 56 b toform cavities 102 having symmetrical shapes as shown, for example, inFIG. 55 b.

FIGS. 61 a-c show different non-linear tool cross paths 130, 131 and 132for forming different cavity geometries, whereas FIGS. 62 a-c showdifferent linear tool cross paths 133, 134 and 135 for forming differentcavity geometries which may approximate various non-linear tool crosspaths by increasing the number of linear segments during tool movementthrough such tool cross paths. For example, the linear tool cross paths133 and 134 shown in FIGS. 62 a and b may be an approximation of thenon-linear tool cross paths 130 and 131 shown in FIGS. 61 a and b. FIG.62 c, on the other hand, show a cross tool path 135 that progressesmonotonically into the substrate and then pulls out when the cutting orforming process is completed. Also the tools may be moved throughdifferent tool cross paths to form at least some cavities having ridgesthat are curved, segmented or hybrid in shape. Likewise, the tools maybe moved through different cross paths to form at least some of thecavities 140 with at least two irregularly shaped curves 141 and 142 andat least one wavy ridge 143 as shown, for example, in FIG. 55 d.

The various surfaces of the substrates in which the cavities are cut orformed may either be substantially flat as shown in FIGS. 52-54 and57-60. Alternatively the surfaces of the substrates 103 in which thecavities are cut or formed may be curved (including conical) as shown inFIG. 63 or cylindrical as shown in FIG. 64. FIG. 63 also shows thecurved substrate 103 moving in an arc, whereas FIG. 64 shows the tool100 moving in a tool cross path during the cut move. Also in FIG. 64both the tool and cylindrical substrate may be positioned to produce aspecific placement for each cavity in the substrate prior to eachcutting or forming process, and the tool may be rotated to produce adifferent orientation for at least some of the cavities prior to cuttingor forming at least some of the cavities. However, it is to beunderstood that either the tool or substrate or both may move duringand/or prior to the cutting or forming process. Also the cavities may becut or formed directly in the surface of the cylindrical substrate or ina sleeve or segment of a sleeve that may be removed from the cylinder.

After the desired number of patterns of optical element shaped cavitiesare cut or formed in the substrates, the substrates containing thedesired pattern or patterns of optical element shaped cavities ordeposition or mirror copies or inverse copies thereof may be used inproduction tooling or as a master for making production tooling. Theproduction tooling may be used to form corresponding patterns of opticalelements on or in optical substrates by molding, thermoforming, hotstamping, embossing, extrusion, or radiation curing and the like. Forexample, FIG. 65 shows tooling 150 placed in an injection mold 151 formolding optical elements on or in optical substrates; FIG. 66 showsforming the optical elements on or in optical substrates by applyingheat and pressing the optical substrate 152 against the optical elementshaped cavities in the tooling 150; and FIG. 67 shows forming theoptical elements on or in the optical substrate formed by applying aflowable optical substrate material 153 over the optical element shapedcavities in the tooling 150 and having the flowable optical substratematerial cure or solidify before removing the cured or solidifiedoptical substrate material from the tooling. The flowable opticalsubstrate material may, for example, be a self-curing material or anultraviolet or other radiation curing material.

Where the cavities are formed in a cylindrical substrate, the cylinderitself may be used as the production tooling to form a correspondingpattern of optical elements on a roll of the optical substrate by anembossing or extrusion process or the like.

Although the invention has been shown and described with respect tocertain embodiments, it is obvious that equivalent alterations andmodifications will occur to others skilled in the art upon the readingand understanding of the specification. In particular, with regard tothe various functions performed by the above described components, theterms (including any reference to a “means”) used to describe suchcomponents are intended to correspond, unless otherwise indicated, toany component which performs the specified function of the describedcomponent (e.g., that is functionally equivalent), even though notstructurally equivalent to the disclosed component which performs thefunction in the herein illustrated exemplary embodiments of theinvention. In addition, while a particular feature of the invention mayhave been disclosed with respect to only one embodiment, such featuremay be combined with one or more other features of other embodiments asmay be desired and advantageous for any given or particular application.

1. A method of forming a pattern of optical elements on or in at leastone side of an optical panel member, the method comprising: cutting orforming a pattern or patterns of cavities in a cylindrical or curvedsubstrate or in a sleeve or sleeve segment of the substrate using acutting tool that is moved into and out of engagement with the substrateor sleeve or sleeve segment and has a tool axis that extends at an acuteangle to the substrate or sleeve or sleeve segment while the cuttingtool is moved in a non-parallel cross path direction to the substrate orsleeve or sleeve segment, the cutting tool comprising a cutting orforming tip that is nonsymmetrical about the tool axis, the cutting orforming tip having at least one cutting or forming edge that is parallelto the cutting tool cross path direction in order to cut or form thepattern or patterns of cavities in the substrate or sleeve or sleevesegment during the cutting or forming process, the pattern or patternsof cavities corresponding to a desired pattern and shape of opticalelements to be formed on or in the optical panel member, using thesubstrate or sleeve or sleeve segment containing the desired pattern orpatterns of optical element shaped cavities or depositions or mirrorcopies or inverse copies thereof in production tooling or as a masterfor production tooling, and using the production tooling to form thecorresponding pattern of optical elements on or in at least the one sideof the optical panel member.
 2. The method of claim 1 wherein at leastsome of the cavities that are cut or formed in the substrate or in thesleeve or sleeve segment during the cutting or forming process vary insize.
 3. The method of claim 1 wherein at least some of the cavitiesthat are cut or formed in the substrate or in the sleeve or sleevesegment during the cutting or forming process vary in height or depth.4. The method of claim 1 wherein at least some of the cavities that arecut or formed in the substrate or in the sleeve or sleeve segment duringthe cutting or forming process vary in orientation or placement.
 5. Themethod of claim 1 wherein at least some of the cavities that are cut orformed in the substrate or in the sleeve or sleeve segment during thecutting or forming process vary randomly.
 6. The method of claim 1wherein at least some of the cavities that are cut or formed in thesubstrate or in the sleeve or sleeve segment during the cutting orforming process vary in shape or type.
 7. The method of claim 1 whereinat least some of the cavities that are cut or formed in the substrate orin the sleeve or sleeve segment during the cutting or forming processvary in angle or rotation.
 8. The method of claim 1 wherein at leastsome of the cavities that are cut or formed in the substrate or in thesleeve or sleeve segment during the cutting or forming process overlap,intersect, or interlock with other optical elements.
 9. The method ofclaim 1 wherein the substrate or the sleeve or sleeve segment in whichthe cavities are formed is used to form the corresponding pattern ofoptical elements on or in at least the one side of the optical panelmember by molding, thermoforming, hot stamping, embossing, extrusion, orradiation curing.
 10. The method of claim 1 wherein the cavities are cutor formed directly in the sleeve or sleeve segment and the sleeve orsleeve segment is then removed from the cylindrical substrate and usedto produce the corresponding pattern of optical elements on or in atleast the one side of the optical panel member.
 11. The method of claim1 wherein the optical panel member is removed from a roll or largeroptical substrate.
 12. The method of claim 1 wherein the optical panelmember has multiple layers.
 13. The method of claim 1 wherein theoptical elements are formed by a UV curing process.
 14. The method ofclaim 1 wherein the optical panel member is formed by applying aflowable optical material to the cylindrical or curved substrate or thesleeve or sleeve segment containing the varying pattern or patterns ofcavities and curing the optical material.
 15. The method of claim 1wherein the cavities are formed in the substrate or in the sleeve orsleeve segment which is used as the production tooling to form thecorresponding pattern of varying optical elements on a roll of opticalpanel members by an embossing or extrusion process.
 16. The method ofclaim 1 wherein the cavities are formed in the substrate or in thesleeve or sleeve segment which is used as the production tooling to formthe corresponding pattern of varying optical elements on a roll ofoptical panel members by a UV curing process.
 17. A method of forming apattern of optical elements on or in at least one side of an opticalpanel member that has one input edge for receiving light from at leastone light source, and a greater cross sectional width than thickness,wherein the optical elements are projections or depressions on or in atleast the one side to cause light to be emitted from the panel member ina predetermined output distribution, and wherein the optical elementsvary along at least one of the length and width of the panel member andare quite small relative to the length and width of the panel member,the method comprising: cutting or forming a varying pattern or patternsof cavities in a cylindrical or curved substrate using a cutting toolthat is moved into and out of engagement with the substrate and has atool axis that extends at an acute angle to the substrate while thecutting tool is moved in a non-parallel cross path direction to thesubstrate, the cutting tool comprising a cutting or forming tip that isnonsymmetrical about the tool axis, the cutting or forming tip having atleast one cutting or forming edge that is parallel to the cutting toolcross path direction in order to cut or form the pattern or patterns ofcavities in the substrate during the cutting or forming process, thevarying pattern or patterns of cavities corresponding to a desiredpattern and shape of optical elements to be formed on or in the opticalpanel member, using the substrate containing the desired pattern orpatterns of optical element shaped cavities or depositions or mirrorcopies or inverse copies thereof in production tooling or as a masterfor production tooling, and using the production tooling to form thecorresponding pattern of optical elements on or in at least the one sideof the optical panel member.
 18. The method of claim 17 wherein at leastsome of the cavities that are cut or formed in the substrate during thecutting or forming process vary in one or more of the following: size,height or depth, orientation or placement, randomly, shape or type,and/or angle or rotation.
 19. The method of claim 17 wherein thesubstrate in which the cavities are formed is used to form thecorresponding pattern of optical elements on or in at least the one sideof the optical panel member by molding, thermoforming, hot stamping,embossing, extrusion, or radiation curing.
 20. The method of claim 17wherein the optical panel member is removed from a roll or largeroptical substrate.
 21. The method of claim 17 wherein the opticalelements are formed by a UV curing process.
 22. The method of claim 17wherein the optical panel member is formed by applying a flowableoptical material to the cylindrical or curved substrate containing thevarying pattern or patterns of cavities and curing the optical material.23. The method of claim 17 wherein the cavities are formed in thecylindrical substrate which is used as the production tooling to formthe corresponding pattern of varying optical elements on a roll ofoptical panel members by an embossing or extrusion process.
 24. Themethod of claim 17 wherein the cavities are formed in the cylindricalsubstrate which is used as the production tooling to form thecorresponding pattern of varying optical elements on a roll of opticalpanel members by a UV curing process.
 25. A method of forming a patternof optical elements on or in at least one side of an optical panelmember that has one input edge for receiving light from at least onelight source, and a greater cross sectional width than thickness,wherein the optical elements are projections or depressions on or in atleast the one side to cause light to be emitted from the panel member ina predetermined output distribution, and wherein the optical elementsvary along at least one of the length and width of the panel member andare quite small relative to the length and width of the panel member,the method comprising: cutting or forming a varying pattern or patternsof cavities in a sleeve or sleeve segment of a cylindrical substrateusing a cutting tool that is moved into and out of engagement with thesleeve or sleeve segment and has a tool axis that extends at an acuteangle to the sleeve or sleeve segment while the cutting tool is moved ina non-parallel cross path direction to the sleeve or sleeve segment, thecutting tool comprising a cutting or forming tip that is nonsymmetricalabout the tool axis, the cutting or forming tip having at least onecutting or forming edge that is parallel to the cutting tool cross pathdirection in order to cut or form the pattern or patterns of cavities inthe sleeve or sleeve segment during the cutting or forming process, thevarying pattern or patterns of cavities corresponding to a desiredpattern and shape of optical elements to be formed on or in the opticalpanel member, using the sleeve or sleeve segment containing the desiredpattern or patterns of optical element shaped cavities or depositions ormirror copies or inverse copies thereof in production tooling or as amaster for production tooling, and using the production tooling to formthe corresponding pattern of optical elements on or in at least the oneside of the optical panel member.
 26. The method of claim 25 wherein thesleeve or sleeve segment in which the cavities are formed is used toform the corresponding pattern of optical elements on or in at least theone side of the optical panel member by molding, thermoforming, hotstamping, embossing, extrusion, or radiation curing.
 27. The method ofclaim 25 wherein the optical panel member is removed from a roll orlarger optical substrate.
 28. The method of claim 25 wherein the opticalelements are formed by a UV curing process.
 29. The method of claim 25wherein the optical panel member is formed by applying a flowableoptical material to the cylindrical or curved substrate containing thevarying pattern or patterns of cavities and curing the optical material.30. The method of claim 25 wherein the sleeve or sleeve substrate inwhich the cavities are formed is used as the production tooling to formthe corresponding pattern of varying optical elements on a roll ofoptical panel members by am embossing or extrusion process.
 31. Themethod of claim 25 wherein the sleeve or sleeve substrate in which thecavities are formed is used as the production tooling to form thecorresponding pattern of varying optical elements on a roll of opticalpanel members by a UV curing process.